She's just popped in (having materialized out of thin air) at the entrance of the Science School, where the school's director, zazen Manbi, and I are about to embark on a tour. "I believe Lilith is an escort," says Manbi, eying her skin-tight catsuit and long black leather boots.

"A hot escort," corrects Forzane. And she is, if one considered her digitized curves and pixelated bedroom eyes "hot" in the traditional sense.

Forzane, Manbi and I are in Second Life, the online virtual world where activities, goals and even scenery are created by the users themselves. Since the program, which is essentially a video game, was launched by Linden Lab in June 2003, millions of people have created walking, talking digital "avatars" of themselves — which, using the game's open-ended design, can look like carbon copies of their user or resemble, say, a talking dolphin — and begun building virtual models of whatever their hearts desire.

It's sort of a three-dimensional version of the Internet, where roughly tens of thousands of Second Life "residents" are logged on at any given moment, exploring this vast realm, socializing with other users and creating and trading virtual property.

The strange online world, which observers have estimated nets Linden Lab about $40 million a year, features many of the quirks of real life. Countries like Sweden, Colombia and Macedonia have opened in-game embassies where people can learn about their countries. Second Life real-estate speculators sell hot-commodity virtual lands to other users, making hundreds of thousands of real dollars a year. Rock bands and theater troupes have performed in Second Life theaters, using microphones and instruments attached to their computers. Avatars waving digital signs have staged in-game protests on everything from IBM union negotiations to potential U.S. military action in Iran.

And of course, lots of people troll for sex. "I'd like to have a hot hour with a geek," Forzane informs us. She's not talking about real sex, but the virtual kind, involving naked, writhing avatars. And since she's an escort, this hot hour probably costs Linden Dollars, the in-game currency that Second Life users can buy with real money, the exchange rate holding reasonably steady at 266 Lindens to one U.S. dollar.

If she's looking for geeks, she's come to the right place, replies Manbi: "There are about fifty islands here for you to find one." The Science School and the tiny virtual island it sits on lie in the center of SciLands, an archipelago of in-game islands owned and populated by some of the foremost science and technology organizations in the world: NASA, the National Oceanic and Atmospheric Administration, the National Library of Medicine and the National Physical Laboratory, to name a few. They're constructing state-of-the-art exhibits, laboratories and classrooms here — things that would be too costly, complicated or downright hazardous to build in real life.

It's like one big science museum planned by some of the brightest minds around, open to anyone anywhere in the world and featuring no closing time and no admission fee. (It's free to sign up for Second Life, though users need to be at least eighteen or they'll be relegated to the Teen Second Life world.) SciLands' creators hope to give science education and advocacy a shot in the arm by invading the world of video games and Internet obsessions that have wreaked havoc on museum attendance rates and homework assignments. Who knows? It may even work.

But while there are certainly a lot of geeks in SciLands, notes Manbi, "chances are there won't be many takers" for Forzane's brand of hands-on experimentation, since everyone's too busy building digital rocket ships or holding in-game conferences on the Large Hadron Collider particle accelerator. He should know: Manbi — or, rather, his flesh-and-blood counterpart, Jeff Corbin — helped found SciLands two years ago.

Forzane, discouraged, teleports away without another word.

That allows Corbin and me, through our avatars, to continue our tour of Science School. We stroll through a verdant landscape dotted with chess sets and solar panels — all of which were constructed by Corbin and other Second Life users with "prims," virtual building blocks. The three-dimensional visuals are impressive — far from photorealistic, but as good as those found in computer games circa 2004. We pass by portals that, with a mouse click, can whisk us to the various reaches of SciLands: virtual rocket lift-offs, a lunar landing site, habitats populated by "cobblefish," "jellypods" and other self-evolving creatures. Considering these exotic locales, our destination is almost mundane in its familiarity: a brick-by-brick re-creation of the F.W. Olin Hall at the University of Denver, digitally designed by Corbin in recognition of his employer.

Compared with the astrophysicists and museum curators behind many of SciLands' key avatars, Corbin, a part-time "media specialist" at DU, used to be small potatoes. But that's changed thanks to his work in SciLands: Corbin's avatar racks up nearly 2,000 hits on Google, he's been a celebrated guest star on the Second Life game show "Second Question," and he can literally move mountains.

"Wanna climb a mountain?" asks Manbi — and so we attack a sheer rock face sprouting behind Olin Hall. When the ascent becomes tedious, I hit a button on my keyboard and my avatar levitates upward, soaring to the top of the peak — where, amid goats and mountain lions, stands a re-creation of DU's Meyer-Womble Observatory on Mount Evans. "An optimized version of the once-highest observatory on earth," says Manbi of the structure, which, along with the mountain, he designed and paid for (buying property in Second Life costs real dough). Eventually, he hopes, the telescope will actually work, letting people all over the world peep into its eyepiece and see images beamed directly from its real-life counterpart.

It makes sense that this DU landmark stands near the center of SciLands. Corbin and DU physics professor Robert Amme have used their development of the Science School to establish DU as a key player in this online science consortium, and the university now enjoys a hefty reputation in online science and technology circles.

If only they could get the real school to care.

So far, DU administrators haven't gotten on board with Second Life, but they may have to soon as a result of Corbin and Amme's latest and most ambitious endeavor.

"Have I shown you the core?" asks Manbi, referring to the nuclear reactor being built under his direction with help from a Nuclear Regulatory Commission grant. With a whoosh of blackness, we teleport away to the reactor's construction site, with Manbi, at the last moment, noting ominously, "It's still unfinished."

Can virtual people be harmed by virtual fallout?

Back in the real world, hidden away in DU's physics building, is a small, cluttered room behind a door marked "Defect Products," where Corbin oversees the Science School. Two computer screens, one showing Second Life, sit perched amid Doritos bags and soup cans, piles of paper and tangles of electrical cords.

Corbin himself sort of resembles his eyeglass-wearing avatar, though Manbi has a lot less grey hair, prefers neat button-downs to Corbin's rumpled Hawaiian shirts, and exudes calm confidence where Corbin displays hints of nervous awkwardness. Manbi can also fly, which he's doing right now, soaring over the Science School.

The land below — including a detailed version of the Rose Center for Earth and Science in New York City, complete with working exhibits — is largely vacant.

While the Science School features enough interesting exhibits and buildings to attract a small but steady stream of visitors — science geeks, professors, college students, random avatars out for a stroll — its big draw is the open-air auditorium, which hosts the weekly in-game version of the hit NPR show Science Friday.

During a recent show, a small crowd sat in the venue, chatting via text windows about the day's topic and asking questions to "Ira Flately," the virtual radio-show host. It's sort of like being at a real-world taping of the show, the difference being that attendees are pirates and aliens and a Barack Obama look-alike with angel wings. On this occasion, turnout was just a few dozen, though Corbin notes that the event has drawn hundreds. "I've met so many people," he says. "What cracks me up is I became famous through my avatar."

Corbin is the perfect fit for his virtual museum curatorial duties. He's always been an idiosyncratic tinkerer, obsessed with capturing the intricacies of science. Growing up the son of an oil worker whose job took the family from Aspen to Libya to Casper, Wyoming, Corbin preferred losing himself in his chemistry set to excelling at schoolwork. "I wanted to make a bomb," he explains. "As kids like to do."

He didn't go to college, at least not in the traditional sense. While living in Denver in 1984, he spotted a National Geographic with a first-of-its-kind holographic cover, and its murky three-dimensional eagle blew his mind. "I have to do this," he said, so he enrolled in the San Francisco School of Holography, one of a number of such schools that opened in the 1970s, where he learned to make the images with lasers, lenses and beam splitters.

When he got back to Denver, he became volunteer assistant director at the one place around that might possibly use his training: the Colorado Science Center, a hands-on science museum then based in City Park Pavilion. He loved every part of the Science Center: its two-way mirrors, its sparking electrodes, its Mars Viking Lander model. "It really turned me on to the hands-on aspect of science," he says. "Kids wouldn't be so turned off by science if they could play with it."

Corbin wasn't the only one interested in turning kids back on to science. The Second International Science Study, conducted between 1982 and 1986, found that U.S. high school students were trailing many European and Asian countries in science achievement, and were even doing worse than their American counterparts from the 1970s.

Corbin befriended another Science Center volunteer who was equally passionate about figuring out what had gone wrong in science classrooms: Robert Amme, a DU physics professor with a fashion sense as colorful as his academic interests. Over the years, Amme has spearheaded projects to transform coal plant waste into usable concrete, to reuse tires as paving for recreation trails, and, possibly hardest of all, to inject enthusiasm back into math and science curricula.

"He's brilliant. He's excited. He has the enthusiasm and curiosity of a kid," says Corbin of his colleague. "Most people link that sense of wonder to neuroses."

"Jeff and I complement each other," adds Amme. "I have the formal training and many, many years of teaching to secondary-school teachers. And Jeff has all the technology know-how. We were a natural pair."

Even this dynamic duo couldn't save the Colorado Science Center, however, which closed in the late 1980s due to dwindling attendance and funds. "That was kind of a drag," says Corbin, who tried unsuccessfully to find a new location.

Instead, he began designing graphics, maps and visual presentations for oil corporations and other high-tech companies around the world. Then, in August 2006, he picked up another magazine that once again changed everything.

It was a copy of Popular Science, and its lead article was all about Second Life.

So, do you want to see the eclipse, Mars or the Big Bang first?"

Patio Plasma's question to me hangs in the digital air for a moment as we stand in the middle of Exploratorium Island, the Second Life wing of the Exploratorium science museum in San Francisco. I'm still coming to grips with the fact that Plasma, the avatar of Paul Doherty, an Exploratorium senior staff scientist, is an attractive woman.

Plasma senses my confusion. "You may notice that Patio is a female avatar," she, er, he says. "I am quite open about having a female avatar. It is, after all, SECOND Life."

The awkwardness somewhat dissipated, I choose Exploratorium's solar eclipse exhibit, just as a group of college students on a virtual school field trip might do. Soon we're riding light balls shooting out of a miniature sun, learning how long these light beams take to reach earth as we zoom across the green terrain. Then we teleport to a red, desolate wasteland — a simulated version of Mars.

"Here comes the meteor," says Plasma — as a gigantic rock throttles out of the sky and slams into the surface just in front of us, spewing fire and debris and leaving a gaping crater we explore at our leisure. Finally, we stop by Plasma's newest exhibit: the Big Bang. We sit on glowing spheres in the middle of an empty room and then, with the announcement, "The Singularity is preparing the creation of the universe," the walls fade away and we're rocketing through space as galaxies form like colorful fireworks in the first moments of time. "Wow," is all I can manage when the Universe tidily resets itself and we're transported back to the exhibit room.

"In Second Life, we can do things too big and too expensive and too dangerous to do in real life," says Plasma. The creation of the entire universe for the Big Bang exhibit, for example, only took Doherty and his museum colleagues three weeks.

Exploratorium Island is one of the most popular places in SciLands, attracting 1,600 to 2,400 unique visitors a month (that's nowhere near the 600,000 visitors the real Exploratorium gets, but Plasma says in-game attendance is constantly growing). It is also, along with the Science School, one of the oldest islands in the archipelago.

Doherty's work at the Exploratorium focuses on helping high-school physics teachers make classes more interesting. He was first introduced to Second Life in January 2006, when the Exploratorium built a Second Life amphitheater where people could get together to concurrently watch a live solar eclipse from the real world projected onto a virtual movie screen in the amphitheater.

"Here is what we discovered," he says. "On the Web, people would watch the eclipse for fifteen minutes, ten minutes, mostly at home, with few family members. It was a personal experience. In Second Life, people would come into the amphitheater, watch the eclipse and stay for an hour, watching the entire partial eclipse, the whole program. And what was happening was, there would be a fanatic from Finland having their avatar sit with a fanatic from Japan and having a conversation about what they were seeing. It took this personal experience of watching it by yourself and made it a social experience. I was blown away by that."

It was easy for Doherty to see the game's educational potential. Here, people from all over the world could come together to learn about, experiment with and talk about science exhibits and telecasts of real-world events whose creation and coordination cost a tiny fraction of what they would in real life — and whose staying power seemed to be much longer than an average class lecture or informational website. So he bought some virtual land — each 65,536 virtual square-meter island costs educational institutions and nonprofits $950, plus a $150-a-month maintenance fee, less than it would for private entities — and started re-creating museum exhibits. Soon he met like-minded avatars, including a shaggy-haired fellow named zazen Manbi who was building a place called the Science School, and they decided to join forces, creating a sub-continent in Second Life devoted to science and technology.

Now SciLands features contributions from roughly two dozen government agencies, universities and museums, many of which are recipients of some of the $6.5 million the National Science Foundation has provided for educational opportunities in Second Life and other virtual worlds. (Second Life is far from the only computer-based simulated environment; the recently released second edition of Blue Book: A Consumer Guide to Virtual Worlds lists more than 250 entries, from massively multi-player online role-playing games to social networks.) SciLands reps hold regular meetings where they plan future projects, decide whether to allow in new island applicants and even fend off takeovers. (The not for-profit New Media Consortium considered buying SciLands, but, Corbin says, "We figured we could hold our own.")

"This is a whole new frontier of education," says Doherty. "We are the pioneers of this field. It's great to get together once a week and say, 'Guess what I just discovered?'"

For Corbin, it's a geeky dream come true. With the help and encouragement of Amme, he'd begun building the Science School as a virtual ode to his lost Colorado Science Center ("If I can't have one in real life, damn it, I'll have one in Second Life"). Now he found himself part of a powerful science partnership, one that had the potential to get video-game-obsessed kids back into science.

"My enthusiasm has been ridiculous on this," he says. "A lot of people thought I was out of my mind, that I was nuts. It was all I talked about." In SciLands, there were just so many interesting people for him to meet, so many cool things to build — so many accomplishments he could achieve. Soon he was spending fifteen hours a day in the game and he blew through his 401(k) paying for the habit, spending roughly $15,000 to $20,000 on a fancy computer system and digital video camera to stream movies into the Science School and $3,000 on virtual land and upkeep (Amme threw in about $2,000 of his own).

And it didn't stop when Corbin turned off the computer: "I dreamed about Second Life in the first few months because I was spending so much time in there."

Corbin and Amme aren't the only Colorado scientists immersing themselves in SciLands. Recently, a spiffily dressed digital fellow named Hackshaven Harford gave me a tour of the twelve SciLands islands maintained by the National Oceanic and Atmospheric Administration's Boulder-based Earth System Research Laboratory.

As with Exploratorium Island, some of the most popular exhibits at NOAA's outpost — which has a real-world budget in the six figures — involve wanton destruction or natural disasters. Harford, the avatar for Eric Hackathorn, who manages NOAA's virtual-world program, escorts me to a tranquil beach lined with bungalows and palm trees. I follow him into the watery depths, where the ocean floor begins to rumble and undulate — to the unexpected tune of '80s dance song "You Spin Me Round (Like a Record)." "It's not very realistic, but it's good for a dance floor," jokes Harford, bobbing up and down.

The demonstration is accurate enough to get the exhibit's safety-themed point across: If the sea floor starts acting like this in real life, time to get out of the water. We do, but unwisely stay on the beach as the water's edge suddenly drops away, exposing a wide stretch of seabed and a stranded fish flopping about. We soon discover that this was a bad idea. A roaring tsunami bears down upon us, inundating the shoreline and leaving behind a wasteland of strewn wreckage. In a flash, however, the digital bungalows are back on the screen, the trees re-grown and the sea once again serene.

"Faster than FEMA," quips Harford.

Next we fly off toward the horizon, until a giant floating globe appears. This is the beginning stage of Hackathorn's plan to create an in-game, three-dimensional model of Google Earth, the hyper-detailed satellite-imagery mapping program. The result could be the weather map to end all weather maps. College students will be able to watch as clouds pile up against the Rocky Mountains. Virtual briefing rooms could be set up here, with officials watching hurricanes track across the globe and planning evacuation and recovery efforts accordingly.

That's not all, says Harford. Imagine, he says, being able to have an avatar walk through a virtual Boulder on this virtual globe. "Imagine a virtual world where you could meet your friend on a virtual Pearl Street and go into a virtual store and try on and buy virtual clothes, and then the real version would be shipped to you." It's not as far-fetched as it sounds; many suggest this could be the next generation of the Internet.

If that's the case, scientists working in Second Life and other virtual worlds will have a leg up. "NOAA sees this as an investment in the future," Hackathorn says. "Maybe it's Second Life, maybe it's another platform, but five, ten years from now, we could be talking about photorealistic environments, avatars that can flow with you from one world to the next, the blurring of the web and virtual worlds into the metaverse."

Hackathorn credits true believers like Corbin with helping spread this gospel — no matter the cost. "Jeff's working hard to get Denver University on board as well as different organizations around Denver," says Hackathorn. "He has hand-carried the non-believers down there into this virtual world, many times at his personal expense."

Impressive as it may look, the Science School's nascent nuclear reactor gets low marks on security. "Here we are in the reactor," reports Manbi as we float straight through the power plant's domed roof, without a single warning siren wailing in alarm. We're surrounded by pipes, walkways and machinery — all of it a bit imposing.

"Can students make it go critical?" I ask, eyeing the foreboding fuel rods. "Will you be able to cause a Chernobyl?"

No, says Manbi: "We're focusing on environmental impact statements" — though my catastrophic question may haven given him ideas: "That should be part of this."

Once it's complete, Second Life's first nuclear reactor will be quite the teaching tool — even though DU at first had little to do with it.

"We didn't have any support from the university," says Amme. "Partially, Jeff saw that coming. That's why he went ahead and bought the first island on his own."

Administrators and professors were still reluctant even when Corbin erected Olin Hall and Meyer-Womble Observatory on his own time and dime. No DU class uses the virtual Olin Hall's auditorium, and no link-up is planned between the simulated telescope and the real one.

"This is something new and something different, and I think whenever you have that, there is a whole continuum of enthusiasm about it ranging from overly optimistic and hopeful to unduly unhopeful and pessimistic," says John Hill, director of environmental policy and management for DU's distance-learning program. "The fact is, we haven't yet established whether it is an effective mode of education."

But last year, as nuclear power experienced an upswing in popularity in the face of the growing worldwide energy crisis, the federal Nuclear Regulatory Commission began looking ways to train people on the hugely complex environmental impact assessments required for new U.S. nuclear power plants. In response, Amme, Corbin and DU physics professor Zeev Shayer proposed a distance-learning master's degree program where some of the physics experiments — usually impossible to simulate in online courses — would be conducted in a virtual physics lab on Science Island. This would also allow students to access and work with simulated versions of potentially hazardous and expensive radioactive materials. Finally, the distance learners could even go on field trips — to a virtual nuclear reactor.

Soon the Science School had real funding, part of a $200,000 grant the NRC awarded DU's University College, a distance-learning and continuing-education school, to develop the master's program. Now Corbin is overseeing the creation of a virtual physics wing by a professional Second Life "construction company": Aimee Weber Studio, a virtual world-content developer that works mostly for government agencies and charges on average $25,000 to $30,000 a project.

Regular Joes like Corbin could build it all themselves, says Aimee Weber over the phone from New Jersey, but, she adds, "there is a different level of quality between a Hollywood blockbuster and a homemade film.

"A nuclear reactor is something I have wanted to do for a while," Weber continues. "Very few people have the opportunity to go inside a nuclear reactor. Suppose you have security clearance and you go into a nuclear power plant. If you are talking about getting next to a nuclear power core, you really can't do that, unless you have a death wish."

Weber is basing the power plant on a cardboard model Amme and Corbin obtained of a real reactor in Finland, while her chief technical officer Brian Mobbs is developing working Geiger-Müller counters, gamma-ray spectrometers and other gadgets for the physics lab. The project is almost complete; a few more experiments need to be built and the power plant control room has to be copied and pasted into place. Classes may begin next semester, and will include non-Second Life alternatives for students who don't want or don't have the tech capabilities (a high-speed Internet connection and a computer with at least 512 megabytes of memory) to run the program — though, as Amme says, "Their experience will not be as rich."

Now others at DU seem to be paying attention. "Can you imagine if we really succeed, if we get twenty students into this laboratory to do physics experiments?" says Hill excitedly. "Putting them into a nuclear control room and letting them do things and destroy things and not letting them get hurt? Think of what this means. Imagine how powerful this can be for education."

But not everyone was thrilled when the story hit the online newspaper Inside Higher Ed last year. "Second Life isn't stable enough to test something that important," one commenter wrote. "Why not make a program that will actually simulate that properly? Second Life doesn't even stand up to normal 'game' quality. It can't even properly simulate a car."

Second Life's graphics and social buzz may be so 2006, but as Corbin points out, it's powerful and user-friendly enough that institutions around the world, from Oakland University in Michigan to Imperial College London, are using it — with notable results. There are reportedly over a hundred parts of Second Life dedicated to educational purposes (mostly post-secondary education, considering the age restrictions), and more than 80 percent of British universities are said to have a presence in the game.

"This is exactly the kind of environment you can construct for teaching," says Mary Anne Clark, a biology professor at Texas Wesleyan University who's using the program with her students. "It is so interactive, you can make it attractive, and it is social. You have the same kind of social interactions you would have in a classroom. You also get the increased flexibility you get from online courses."

Clark's students undertake genetic experiments in greenhouses she built in SciLands and tour a human cell she constructed that's the size of an in-game house. She notes that while she has yet to thoroughly assess the medium, students have seemed to do better on her virtual labs than her real ones.

Sure, acknowledges Doherty, the open-endedness of Second Life and the anonymity of avatars allow escorts to pop in unexpectedly and even allows folks to strip naked and get it on in the middle of respectable SciLands institutions — as happened once at Exploratorium Island — but that just makes the learning experience more realistic.

Corbin, far away from his computer screen, eyes the colossal plesiosaur skeleton and astronaut mock-up above him with skepticism. He's never been that impressed with the Denver Museum of Nature & Science — there are just too many static stuffed animals and staid mummy displays, and not enough buttons to push or levers to pull. In other words, it ain't no Colorado Science Center. When he walks by dioramas of Colorado wildlife, he grumbles, "If you want to do better, go to the zoo."

He perks up a bit when he wanders into the newer, more interactive space wing. "This is kind of hands-on," he notes of a water table covered in red sand where visitors can re-create the river channels and deltas on Mars — though he already wants to know just how far he can take the demonstration: "As a kid, I would have wanted to build a dam and try to build a lake." When a boy comes up and starts pushing the wet sand this way and that, Corbin grins. "Yeah, he's doing it right."

One day the Science School might have exhibits like this — though Corbin is in no rush to build them himself. "I got burned out," he says of his fifteen-hour days in SciLands. One impetus for this may have been when he lost his desk job at a hydrology company — not long after he started logging into Second Life at work. Now Corbin, who still does freelance jobs for energy companies when he's not working at DU, rations his time, leaving most of the construction to professionals like Aimee Weber.

That's not to say he's done with Second Life — far from it. He and Amme have big plans for SciLands. Maybe they'll make an underground uranium mine to go along with the reactor. Or a working Jules Verne time machine, or a submarine that travels through the human body à la Fantastic Voyage. Corbin would love to develop a Science School curriculum to be used in struggling rural classrooms "where gym teachers teach science."

And then there's his big dream: To reopen the Colorado Science Center — not in SciLands, but in the old-fashioned world. "In my mind, nothing replaces the real thing," he admits. Just take this water table, he adds: "I suppose someone could simulate this in Second Life, but it wouldn't be the same. You couldn't get your hands dirty."